Esophageal and Airway pH Monitoring
Customize your policy alerts
Sign up for Aetna Policy 0667 alerts
Get alerted when Policy 0667 changes without checking for updates manually.
Monitor payer policy activity
Clinical coverage rules for esophageal and airway pH monitoring technologies (catheter-based, catheter-free Bravo, multichannel intraluminal impedance variants) and indications for adults and children, specifying medically necessary versus experimental/investigational uses for Aetna members.
Coverage criteria — esophageal and airway pH monitoring
inv-01: Medically Necessary: Esophageal pH monitoring
Esophageal pH monitoring is considered medically necessary when any one of the following indications is met:
inv-02: Bravo pH monitoring
The capsule (Bravo) system may be used as an alternative to catheter-based monitoring except where specifically contraindicated:
inv-03: MII and combined testing
Coverage stance for multichannel intraluminal impedance (MII) and combined testing modalities:
MII is considered investigational for other indications (eg, achalasia, laryngo-pharyngeal reflux).
inv-04: Experimental and Investigational
The following devices and test applications are considered experimental or investigational and are not covered because effectiveness has not been established:
inv-05: Coverage rationale / investigational stance
Summary coverage rationale and investigational designation from guideline and technology assessments:
Statement reflects summaries from AGA, AHRQ, and Centre for Evidence-based Purchasing assessments.
References include AGA technical review, AHRQ assessment, and SAGES guideline summaries.
inv-06: Indications for MII-pH and Manometry
MII-pH and manometry are covered when testing is indicated to diagnose or further characterize reflux in these clinical scenarios:
Whether testing is performed on or off PPI therapy depends on the indication: for refractory symptoms administer high-dose PPI prior to testing; to clarify if GERD is the cause of symptoms, perform testing off PPIs.
inv-07: Utility versus conventional pH monitoring
Comparative rationale: when impedance adds diagnostic value compared with conventional pH monitoring:
Clinical impact and effects on outcomes remain limited by the quality of available studies.
inv-08: Airway impedance (investigational)
Airway impedance measurement at the larynx is considered investigational:
Further validation in larger cohorts and correlation with clinical outcomes are required before routine clinical use.
The disposable capsule pH monitor (Bravo pH Monitoring System) is considered an acceptable alternative to standard catheter-based ambulatory pH monitoring for the medically necessary indications in this policy except for evaluating vomiting in infants, because the Bravo system has not been approved for use in that age group and therefore is not acceptable for infant vomiting assessment.
Multichannel intraluminal impedance combined with pH monitoring (MII-pH) is described in this policy as investigational/experimental for routine evaluation of adult GERD because the peer‑reviewed literature and technology assessments show inadequate high‑quality evidence for improved clinical outcomes; professional society reviews and technology assessments have found the evidence inconclusive and lacking rigorous outcome trials.
Interpretation of impedance and combined MII-pH testing must consider the testing context, including whether the study is performed on or off proton pump inhibitor (PPI) therapy. For refractory GERD symptoms clinicians often administer high‑dose PPI (e.g., twice daily) for at least 1 week before MII-pH to detect weakly acidic reflux, whereas when the causal role of reflux is uncertain testing is typically performed off PPIs to maximize detection. Documentation of PPI status and the clinical indication should accompany testing because results and clinical interpretation differ by therapy status.
Typical indications for esophageal pH recording include: verification of abnormal esophageal acid exposure in endoscopy‑negative patients being considered for anti‑reflux surgery; evaluation of suspected reflux‑related extra‑esophageal symptoms (for example chronic cough, laryngitis, or chest pain) after an appropriate PPI trial; documentation of concomitant GERD in adult‑onset non‑allergic asthma when testing is performed off anti‑secretory drugs; assessment of ongoing reflux after anti‑reflux surgery; and evaluation of infants with vomiting up to 3 months of age (with modality‑specific exclusions such as Bravo not approved for infant vomiting). pH recording is also used for detection/verification of reflux esophagitis and other diagnostic questions listed in the policy, though some of these specific uses are considered investigational.
Pharyngeal (oropharyngeal) pH monitoring has important limitations and may substantially over‑estimate supra‑esophageal gastric reflux when used alone. Studies comparing Dx‑pH/OP pH monitoring with concurrent esophageal MII‑pH show many oropharyngeal pH events are not temporally correlated with esophageal reflux events, and the use of extended or alternative pH thresholds increases detected OP events while the majority remain unrelated to GER episodes, suggesting potential artifact and over‑estimation risk.
The intended role of MII‑pH testing is to characterize reflux when symptoms persist despite therapy or when it is clinically necessary to distinguish acid versus non‑acid (weakly acidic) reflux. MII‑pH can detect reflux independent of pH and identify weak acid reflux (pH 4–7), which is useful in patients with incomplete or no response to PPI therapy and in evaluation of atypical extra‑esophageal symptoms; however, routine use without appropriate indication is not supported by the evidence and MII‑pH is considered investigational for many adult GERD indications.
Coding and thresholds
| 91034 | Esophagus, gastroesophageal reflux test; with nasal catheter pH electrode(s) placement, recording, analysis and interpretation. |
| 91035 | with mucosal attached telemetry pH electrode placement, recording, analysis and interpretation. |
| 91037 | Esophageal function test, gastroesophageal reflux test with nasal catheter intraluminal impedance electrode(s) placement, recording, analysis and interpretation. |
| 91038 | Esophageal function test, gastroesophageal reflux test with nasal catheter intraluminal impedance electrode(s) placement, recording, analysis and interpretation; prolonged (greater than 1 hour, up to 24 hours). |
| 91010 | Esophageal motility (manometric study of the esophagus and/or gastroesophageal junction) study with interpretation and report. |
| K21.00 - K21.9 | Gastro-esophageal reflux disease. |
| R05.1 - R05.9 | Cough. |
| R07.9 | Chest pain, unspecified. |
| J45.20 - J45.50 | Intermittent and persistent asthma, uncomplicated. |
| K22.70 - K22.719 | Barrett's esophagus. |
| P92.01 - P92.09 | Bilious and other vomiting in newborn. |
| Q39.0 - Q39.1 | Atresia of esophagus [in children]. |
| R11.10 - R11.14 | Vomiting. |
Provider actions, prior authorization & documentation
Obtain authorization for covered CPTs when criteria are met
CPT codes for esophageal pH and impedance testing (e.g., 91010, 91034, 91035, 91037, 91038) are covered only when the patient's clinical presentation meets the policy's selection criteria; providers should obtain prior authorization when submitting these codes with corresponding indications.
Prior authorization may be affected by investigational MII‑pH status
Because multichannel intraluminal impedance combined with pH monitoring (MII-pH) is described as investigational/experimental for certain GERD indications, prior authorization requests for MII‑pH for those indications may be denied or require additional review.
- Policy states MII-pH is considered investigational/experimental due to inadequate evidence for some GERD indications.
- Payer prior authorization decisions may reflect this investigational designation.
Authorization must reflect indication and PPI on/off status
Prior authorization and claim submission should explicitly state the clinical indication for testing and whether the study will be performed on or off PPI therapy, since the appropriate testing context depends on the indication.
- Decision to perform MII-pH on or off PPI therapy should be based on the underlying indication (e.g., refractory symptoms vs diagnostic clarification).
- Policy notes testing intent (detect weakly acidic reflux vs optimize detection) varies with PPI status.
Follow administrative prior authorization processes
The policy does not list a discrete set of CPT/HCPCS codes that universally require prior authorization; providers should follow plan-specific administrative prior authorization processes and submit clinical justification tied to the policy criteria.
- Chunks do not specify particular CPT/HCPCS codes that always require prior authorization.
- Use clinical documentation matched to the policy's medically necessary indications when requesting authorization.
Document PPI trial of at least 4 weeks before testing when indicated
For several medically necessary indications the policy expects a therapeutic trial of a proton pump inhibitor (PPI) for at least 4 weeks before pH testing to assess symptom response.
- Examples: chest pain after cardiac evaluation and otolaryngologic manifestations should have PPI trial ≥4 weeks prior to pH study when indicated.
- Therapeutic PPI trial is a commonly used clinical alternative and is referenced as part of testing indications.
Consider empiric anti-reflux therapy before advanced testing
Empiric anti-reflux therapy (for example, PPI therapy) is described in the policy as a common initial clinical approach for suspected reflux-related symptoms and should be considered before advanced testing when clinically appropriate.
- Xu et al (2014) note empirical therapy is recommended as an initial approach for GER-induced chronic cough.
- MII-pH is discussed as a diagnostic tool after empiric therapy when symptoms persist.
Use MII‑pH when symptoms persist after empiric therapy
When symptoms persist after empiric therapy (for example inadequate response to PPI), MII‑pH testing can be used to characterize acid versus non‑acid reflux and help guide further management.
- Policy indicates MII‑pH is intended to determine whether non‑acid reflux is causing ongoing symptoms in patients with incomplete or no response to PPIs.
- Use MII‑pH to characterize reflux when empiric therapy response is inadequate.
Document pre-test PPI/anti-secretory status and symptom timing
Document the patient's pre-test medication status (on or withheld anti-secretory drugs) and symptom pattern relative to the test, since several medically necessary indications require testing either after a PPI trial or after withholding anti‑secretory drugs for >1 week.
- Examples in policy: studies to confirm excessive acid exposure are done after withholding anti-secretory drugs ≥1 week; refractory-symptom testing may be done while continuing anti-secretory regimen.
- Symptom–reflux association documentation (e.g., symptom association probability) is preferred for some indications.
Include concurrent endoscopy, histology, and atopy data in pediatric EoE/EA reports
In pediatric evaluations for esophageal atresia or eosinophilic esophagitis, document concurrent diagnostic testing (upper endoscopy with histology) and relevant findings such as atopy or peripheral eosinophilia when reporting pH‑impedance results.
- Studies cited required all patients to undergo upper GI endoscopy and pH‑impedance monitoring.
- Policy notes that atopy and peripheral eosinophilia were predictive factors and should be documented.
Record test context: indication and on/off PPI status
Always state in the record whether MII‑pH testing was performed on or off PPI therapy and the clinical indication for the test (e.g., refractory GERD symptoms, atypical symptoms, preoperative evaluation).
- Policy and UpToDate guidance specify that the decision to test on or off PPIs depends on the indication and affects interpretation.
- Documentation of test context supports appropriate interpretation and authorization.
Include policy history/administrative references in authorization documentation
Document the policy version, review dates, and administrative links in the patient's authorization or chart note when relevant; the policy history and administrative resources are provided in the bulletin.
- Policy history includes last review date 09/25/2023, effective date 07/22/2003, and next review 07/25/2024.
- Administrative links (definitions, review history) are available via the policy bulletin.
Investigational MII‑pH indications may be denied without justification
Claims for MII‑pH testing for GERD indications described as investigational/experimental in the policy are at risk for denial; include supporting clinical justification and reference to specific medically necessary criteria when requesting coverage.
- Policy states MII‑pH is investigational/experimental for evaluation of GERD where evidence is inadequate.
- Prior authorization requests for these indications may be denied without strong supporting documentation.
Document indication plus PPI on/off status to avoid denial
Failure to document the clinical indication and whether testing was performed on or off PPI therapy may result in inappropriate interpretation or denial; record both the indication and PPI status in the preauthorization and operative/report notes.
- Policy emphasizes the decision to perform testing on or off PPI therapy should be indication‑driven.
- Documenting PPI status and indication is necessary for correct test interpretation and coverage decisions.
Background and evidence summary
Esophageal pH monitoring quantifies esophageal acid exposure and provides measures of symptom–reflux correlation but does not by itself prove causality between reflux events and symptoms. Standard catheter-based ambulatory pH monitoring typically records for 24–48 hours; the Bravo wireless capsule is an endoscopically attached, catheter‑free alternative that transmits pH data for multiple days and may be better tolerated. Clinically, a therapeutic trial of a proton pump inhibitor (PPI) is commonly used prior to testing in several indications to assess symptom response, and pH testing should be interpreted in the context of pre‑test medication status.
Definitions and test descriptions
Policy history and review dates
Policy became effective.
Policy was last reviewed and updated.
Next scheduled policy review date.
OpenPayer is powered by Trek Health's payer performance platform. Trek continuously ingests, validates, and normalizes Transparency in Coverage data alongside payer policies and other commercial payer data to create a structured payer intelligence foundation. OpenPayer uses this foundation to deliver personalized search results, dynamically generated policy pages, and tailored policy monitoring based on each user's payers, specialties, billing codes, and areas of interest. The same intelligence powers broader payer performance workflows, including reimbursement benchmarking, contract evaluation, payer negotiations, and financial decision-making.